If $11 \%$ of the power of a $200 \ W$ bulb is converted to visible radiation,then the intensity of the light at a distance of $100 \ cm$ from the bulb is (in $W \ m^{-2}$)

The electric field of a plane electromagnetic wave is given by $\overrightarrow{E} = E_{0} \frac{\hat{i}+\hat{j}}{\sqrt{2}} \cos (kz+\omega t)$. At $t=0$,a positively charged particle is at the point $(x, y, z) = (0, 0, \frac{\pi}{k})$. If its instantaneous velocity at $t=0$ is $v_{0} \hat{k}$,the force acting on it due to the wave is

Which of the following is a wrongly matched pair?

The graph between radiation power $P$ from a linear antenna and the square of the length of the antenna $l^2$ is shown in the figure for two antennas $A$ and $B$. If all other parameters are the same,find the ratio of the wavelengths of $A$ and $B$,i.e.,$\frac{\lambda_A}{\lambda_B}$.

Due to the tilting of the Earth,which waves finally disappear?

If two linear antennas having lengths in the ratio $2: 3$ are emitting radiation of wavelengths in the ratio $8: 9$, then the ratio of effective powers radiated by them are in the ratio